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Java library for reading and writing FITS files. FITS, the Flexible Image Transport System, is the format commonly used in the archiving and transport of astronomical data.
package nom.tam.image.compression.hdu;
import java.nio.Buffer;
import nom.tam.fits.BinaryTable;
import nom.tam.fits.FitsException;
import nom.tam.fits.Header;
import nom.tam.fits.HeaderCard;
import nom.tam.fits.compression.algorithm.api.ICompressOption;
import nom.tam.fits.header.Compression;
import nom.tam.image.compression.tile.TiledImageCompressionOperation;
import nom.tam.util.ArrayFuncs;
/*
* #%L
* nom.tam FITS library
* %%
* Copyright (C) 1996 - 2024 nom-tam-fits
* %%
* This is free and unencumbered software released into the public domain.
*
* Anyone is free to copy, modify, publish, use, compile, sell, or
* distribute this software, either in source code form or as a compiled
* binary, for any purpose, commercial or non-commercial, and by any
* means.
*
* In jurisdictions that recognize copyright laws, the author or authors
* of this software dedicate any and all copyright interest in the
* software to the public domain. We make this dedication for the benefit
* of the public at large and to the detriment of our heirs and
* successors. We intend this dedication to be an overt act of
* relinquishment in perpetuity of all present and future rights to this
* software under copyright law.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
* #L%
*/
/**
* FITS representation of a compressed image. Compressed images are essentially stored as FITS binary tables. They are
* distinguished only by a set of mandatory header keywords and specific column data structure. The image-specific
* header keywords of the original image are re-mapped to keywords starting with 'Z' prefixed so as to not interfere
* with the binary table description. (e.g. NAXIS1 of the original image is stored as ZNAXIS1 in the compressed table).
*
* @see CompressedImageHDU
*/
@SuppressWarnings("deprecation")
public class CompressedImageData extends BinaryTable {
/**
* tile information, only available during compressing or decompressing.
*/
private TiledImageCompressionOperation tiledImageOperation;
/**
* Creates a new empty compressed image data to be initialized at a later point
*/
protected CompressedImageData() {
super();
}
/**
* Creates a new compressed image data based on the prescription of the supplied header.
*
* @param hdr The header that describes the compressed image
*
* @throws FitsException If the header is invalid or could not be accessed.
*/
protected CompressedImageData(Header hdr) throws FitsException {
super(hdr);
}
@Override
public void fillHeader(Header h) throws FitsException {
super.fillHeader(h);
h.addValue(Compression.ZIMAGE, true);
h.deleteKey(Compression.ZTABLE);
}
/**
* Returns the class that handles the (de)compression of the image tiles.
*
* @return the class handling the (de)compression of the image tiles.
*/
private TiledImageCompressionOperation tiledImageOperation() {
if (tiledImageOperation == null) {
tiledImageOperation = new TiledImageCompressionOperation(this);
}
return tiledImageOperation;
}
/**
* This should only be called by {@link CompressedImageHDU}.
*/
@SuppressWarnings("javadoc")
protected void compress(CompressedImageHDU hdu) throws FitsException {
discardVLAs();
tiledImageOperation().compress(hdu);
}
/**
* This should only be called buy{@link CompressedImageHDU}.
*/
@SuppressWarnings("javadoc")
protected void forceNoLoss(int x, int y, int width, int heigth) {
tiledImageOperation.forceNoLoss(x, y, width, heigth);
}
/**
* Returns the compression (or quantization) options for a selected compression option class. It is presumed that
* the requested options are appropriate for the compression and/or quantization algorithm that was selected. E.g.,
* if you called setCompressionAlgorithm({@link Compression#ZCMPTYPE_RICE_1}), then you can retrieve
* options for it with this method as
* getCompressOption({@link nom.tam.fits.compression.algorithm.rice.RiceCompressOption}.class).
*
* @param The generic type of the compression class
* @param clazz the compression class
*
* @return The current set of options for the requested type, or null if there are no options or
* if the requested type does not match the algorithm(s) selected.
*
* @see nom.tam.fits.compression.algorithm.hcompress.HCompressorOption
* @see nom.tam.fits.compression.algorithm.rice.RiceCompressOption
* @see nom.tam.fits.compression.algorithm.quant.QuantizeOption
*/
protected T getCompressOption(Class clazz) {
return tiledImageOperation().compressOptions().unwrap(clazz);
}
/**
* This should only be called by {@link CompressedImageHDU}.
*/
@SuppressWarnings("javadoc")
protected Buffer getUncompressedData(Header hdr) throws FitsException {
try {
tiledImageOperation = new TiledImageCompressionOperation(this).read(hdr);
return tiledImageOperation.decompress();
} finally {
tiledImageOperation = null;
}
}
/**
* This should only be called by {@link CompressedImageHDU}.
*/
@SuppressWarnings("javadoc")
protected void prepareUncompressedData(Object data, Header header) throws FitsException {
tiledImageOperation().readPrimaryHeaders(header);
Buffer source = tiledImageOperation().getBaseType().newBuffer(tiledImageOperation.getBufferSize());
ArrayFuncs.copyInto(data, source.array());
tiledImageOperation().prepareUncompressedData(source);
}
/**
* preserve the null values in the image even if the compression algorithm is lossy.
*
* @param nullValue the value representing null for byte/short and integer pixel values
* @param compressionAlgorithm compression algorithm to use for the null pixel mask
*/
protected void preserveNulls(long nullValue, String compressionAlgorithm) {
tiledImageOperation().preserveNulls(nullValue, compressionAlgorithm);
}
/**
* Sets the size of the image to be compressed.
*
* @param axes the image size
*
* @return itself This should only be called by {@link CompressedImageHDU}.
*/
protected CompressedImageData setAxis(int[] axes) {
tiledImageOperation().setAxes(axes);
return this;
}
/**
* Sets the compression algorithm that was used to generate the HDU.
*
* @param compressAlgorithmCard the FITS header card that specifies the compression algorithm that was used.
*
* @see #setQuantAlgorithm(HeaderCard)
*/
protected void setCompressAlgorithm(HeaderCard compressAlgorithmCard) {
tiledImageOperation().setCompressAlgorithm(compressAlgorithmCard);
}
/**
* Sets the quantization algorithm that was used to generate the HDU.
*
* @param quantAlgorithmCard the FITS header card that specifies the quantization algorithm that was used.
*
* @throws FitsException if no algorithm is available by the specified name
*
* @see #setCompressAlgorithm(HeaderCard)
*/
protected void setQuantAlgorithm(HeaderCard quantAlgorithmCard) throws FitsException {
tiledImageOperation().setQuantAlgorithm(quantAlgorithmCard);
}
/**
* Sets the tile size to use for sompressing.
*
* @param axes the tile size along all dimensions. Only the last 2 dimensions may differ from 1.
*
* @return itself
*
* @throws FitsException if the tile size is invalid. This should only be called by {@link CompressedImageHDU}.
*/
protected CompressedImageData setTileSize(int... axes) throws FitsException {
tiledImageOperation().setTileAxes(axes);
return this;
}
}
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